Select interneuron clusters determine female sexual receptivity in Drosophila

Abstract

Female Drosophila with the spinster mutation repel courting males and rarely mate. Here we show that the non-copulating phenotype can be recapitulated by the elimination of spinster functions from either spin-A or spin-D neuronal clusters, in the otherwise wild-type (spinster heterozygous) female brain. Spin-D corresponds to the olfactory projection neurons with dendrites in the antennal lobe VA1v glomerulus that is fruitless-positive, sexually dimorphic and responsive to fly odour. Spin-A is a novel local neuron cluster in the suboesophageal ganglion, which is known to process contact chemical pheromone information and copulation-related signals. A slight reduction in spinster expression to a level with a minimal effect is sufficient to shut off female sexual receptivity if the dominant-negative mechanistic target of rapamycin is simultaneously expressed, although the latter manipulation alone has only a marginal effect. We propose that spin-mediated mechanistic target of rapamycin signal transduction in these neurons is essential for females to accept the courting male.